cdgraphics: do not rely on get_buffer() initializing the frame.
[libav.git] / libavcodec / cdgraphics.c
1 /*
2 * CD Graphics Video Decoder
3 * Copyright (c) 2009 Michael Tison
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "avcodec.h"
23 #include "bytestream.h"
24 #include "internal.h"
25
26 /**
27 * @file
28 * @brief CD Graphics Video Decoder
29 * @author Michael Tison
30 * @see http://wiki.multimedia.cx/index.php?title=CD_Graphics
31 * @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg
32 */
33
34 /// default screen sizes
35 #define CDG_FULL_WIDTH 300
36 #define CDG_FULL_HEIGHT 216
37 #define CDG_DISPLAY_WIDTH 294
38 #define CDG_DISPLAY_HEIGHT 204
39 #define CDG_BORDER_WIDTH 6
40 #define CDG_BORDER_HEIGHT 12
41
42 /// masks
43 #define CDG_COMMAND 0x09
44 #define CDG_MASK 0x3F
45
46 /// instruction codes
47 #define CDG_INST_MEMORY_PRESET 1
48 #define CDG_INST_BORDER_PRESET 2
49 #define CDG_INST_TILE_BLOCK 6
50 #define CDG_INST_SCROLL_PRESET 20
51 #define CDG_INST_SCROLL_COPY 24
52 #define CDG_INST_LOAD_PAL_LO 30
53 #define CDG_INST_LOAD_PAL_HIGH 31
54 #define CDG_INST_TILE_BLOCK_XOR 38
55
56 /// data sizes
57 #define CDG_PACKET_SIZE 24
58 #define CDG_DATA_SIZE 16
59 #define CDG_TILE_HEIGHT 12
60 #define CDG_TILE_WIDTH 6
61 #define CDG_MINIMUM_PKT_SIZE 6
62 #define CDG_MINIMUM_SCROLL_SIZE 3
63 #define CDG_HEADER_SIZE 8
64 #define CDG_PALETTE_SIZE 16
65
66 typedef struct CDGraphicsContext {
67 AVFrame frame;
68 int hscroll;
69 int vscroll;
70 } CDGraphicsContext;
71
72 static void cdg_init_frame(AVFrame *frame)
73 {
74 avcodec_get_frame_defaults(frame);
75 frame->reference = 3;
76 frame->buffer_hints = FF_BUFFER_HINTS_VALID |
77 FF_BUFFER_HINTS_READABLE |
78 FF_BUFFER_HINTS_PRESERVE |
79 FF_BUFFER_HINTS_REUSABLE;
80 }
81
82 static av_cold int cdg_decode_init(AVCodecContext *avctx)
83 {
84 CDGraphicsContext *cc = avctx->priv_data;
85
86 cdg_init_frame(&cc->frame);
87
88 avctx->width = CDG_FULL_WIDTH;
89 avctx->height = CDG_FULL_HEIGHT;
90 avctx->pix_fmt = AV_PIX_FMT_PAL8;
91
92 return 0;
93 }
94
95 static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
96 {
97 int y;
98 int lsize = cc->frame.linesize[0];
99 uint8_t *buf = cc->frame.data[0];
100 int color = data[0] & 0x0F;
101
102 if (!(data[1] & 0x0F)) {
103 /// fill the top and bottom borders
104 memset(buf, color, CDG_BORDER_HEIGHT * lsize);
105 memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize,
106 color, CDG_BORDER_HEIGHT * lsize);
107
108 /// fill the side borders
109 for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) {
110 memset(buf + y * lsize, color, CDG_BORDER_WIDTH);
111 memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize,
112 color, CDG_BORDER_WIDTH);
113 }
114 }
115 }
116
117 static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
118 {
119 uint8_t r, g, b;
120 uint16_t color;
121 int i;
122 int array_offset = low ? 0 : 8;
123 uint32_t *palette = (uint32_t *) cc->frame.data[1];
124
125 for (i = 0; i < 8; i++) {
126 color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F);
127 r = ((color >> 8) & 0x000F) * 17;
128 g = ((color >> 4) & 0x000F) * 17;
129 b = ((color ) & 0x000F) * 17;
130 palette[i + array_offset] = r << 16 | g << 8 | b;
131 }
132 cc->frame.palette_has_changed = 1;
133 }
134
135 static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
136 {
137 unsigned ci, ri;
138 int color;
139 int x, y;
140 int ai;
141 int stride = cc->frame.linesize[0];
142 uint8_t *buf = cc->frame.data[0];
143
144 ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
145 ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll;
146
147 if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
148 return AVERROR(EINVAL);
149 if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
150 return AVERROR(EINVAL);
151
152 for (y = 0; y < CDG_TILE_HEIGHT; y++) {
153 for (x = 0; x < CDG_TILE_WIDTH; x++) {
154 if (!((data[4 + y] >> (5 - x)) & 0x01))
155 color = data[0] & 0x0F;
156 else
157 color = data[1] & 0x0F;
158
159 ai = ci + x + (stride * (ri + y));
160 if (b)
161 color ^= buf[ai];
162 buf[ai] = color;
163 }
164 }
165
166 return 0;
167 }
168
169 #define UP 2
170 #define DOWN 1
171 #define LEFT 2
172 #define RIGHT 1
173
174 static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
175 int in_tl_x, int in_tl_y, uint8_t *in,
176 int w, int h, int stride)
177 {
178 int y;
179
180 in += in_tl_x + in_tl_y * stride;
181 out += out_tl_x + out_tl_y * stride;
182 for (y = 0; y < h; y++)
183 memcpy(out + y * stride, in + y * stride, w);
184 }
185
186 static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
187 int color, int w, int h, int stride)
188 {
189 int y;
190
191 for (y = tl_y; y < tl_y + h; y++)
192 memset(out + tl_x + y * stride, color, w);
193 }
194
195 static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
196 int in_tl_x, int in_tl_y, uint8_t *in,
197 int color, int w, int h, int stride, int roll)
198 {
199 if (roll) {
200 cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
201 in, w, h, stride);
202 } else {
203 cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
204 }
205 }
206
207 static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
208 AVFrame *new_frame, int roll_over)
209 {
210 int color;
211 int hscmd, h_off, hinc, vscmd, v_off, vinc;
212 int y;
213 int stride = cc->frame.linesize[0];
214 uint8_t *in = cc->frame.data[0];
215 uint8_t *out = new_frame->data[0];
216
217 color = data[0] & 0x0F;
218 hscmd = (data[1] & 0x30) >> 4;
219 vscmd = (data[2] & 0x30) >> 4;
220
221 h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1);
222 v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1);
223
224 /// find the difference and save the offset for cdg_tile_block usage
225 hinc = h_off - cc->hscroll;
226 vinc = v_off - cc->vscroll;
227 cc->hscroll = h_off;
228 cc->vscroll = v_off;
229
230 if (vscmd == UP)
231 vinc -= 12;
232 if (vscmd == DOWN)
233 vinc += 12;
234 if (hscmd == LEFT)
235 hinc -= 6;
236 if (hscmd == RIGHT)
237 hinc += 6;
238
239 if (!hinc && !vinc)
240 return;
241
242 memcpy(new_frame->data[1], cc->frame.data[1], CDG_PALETTE_SIZE * 4);
243
244 for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
245 memcpy(out + FFMAX(0, hinc) + stride * y,
246 in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
247 FFMIN(stride + hinc, stride));
248
249 if (vinc > 0)
250 cdg_fill_wrapper(0, 0, out,
251 0, CDG_FULL_HEIGHT - vinc, in, color,
252 stride, vinc, stride, roll_over);
253 else if (vinc < 0)
254 cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
255 0, 0, in, color,
256 stride, -1 * vinc, stride, roll_over);
257
258 if (hinc > 0)
259 cdg_fill_wrapper(0, 0, out,
260 CDG_FULL_WIDTH - hinc, 0, in, color,
261 hinc, CDG_FULL_HEIGHT, stride, roll_over);
262 else if (hinc < 0)
263 cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
264 0, 0, in, color,
265 -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
266
267 }
268
269 static int cdg_decode_frame(AVCodecContext *avctx,
270 void *data, int *got_frame, AVPacket *avpkt)
271 {
272 const uint8_t *buf = avpkt->data;
273 int buf_size = avpkt->size;
274 int ret;
275 uint8_t command, inst;
276 uint8_t cdg_data[CDG_DATA_SIZE];
277 AVFrame new_frame;
278 CDGraphicsContext *cc = avctx->priv_data;
279
280 if (buf_size < CDG_MINIMUM_PKT_SIZE) {
281 av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n");
282 return AVERROR(EINVAL);
283 }
284
285 ret = avctx->reget_buffer(avctx, &cc->frame);
286 if (ret) {
287 av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
288 return ret;
289 }
290 if (!avctx->frame_number)
291 memset(cc->frame.data[0], 0, cc->frame.linesize[0] * avctx->height);
292
293 command = bytestream_get_byte(&buf);
294 inst = bytestream_get_byte(&buf);
295 inst &= CDG_MASK;
296 buf += 2; /// skipping 2 unneeded bytes
297 bytestream_get_buffer(&buf, cdg_data, buf_size - CDG_HEADER_SIZE);
298
299 if ((command & CDG_MASK) == CDG_COMMAND) {
300 switch (inst) {
301 case CDG_INST_MEMORY_PRESET:
302 if (!(cdg_data[1] & 0x0F))
303 memset(cc->frame.data[0], cdg_data[0] & 0x0F,
304 cc->frame.linesize[0] * CDG_FULL_HEIGHT);
305 break;
306 case CDG_INST_LOAD_PAL_LO:
307 case CDG_INST_LOAD_PAL_HIGH:
308 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
309 av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n");
310 return AVERROR(EINVAL);
311 }
312
313 cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO);
314 break;
315 case CDG_INST_BORDER_PRESET:
316 cdg_border_preset(cc, cdg_data);
317 break;
318 case CDG_INST_TILE_BLOCK_XOR:
319 case CDG_INST_TILE_BLOCK:
320 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
321 av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n");
322 return AVERROR(EINVAL);
323 }
324
325 ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR);
326 if (ret) {
327 av_log(avctx, AV_LOG_ERROR, "tile is out of range\n");
328 return ret;
329 }
330 break;
331 case CDG_INST_SCROLL_PRESET:
332 case CDG_INST_SCROLL_COPY:
333 if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) {
334 av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n");
335 return AVERROR(EINVAL);
336 }
337
338 cdg_init_frame(&new_frame);
339 ret = ff_get_buffer(avctx, &new_frame);
340 if (ret) {
341 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
342 return ret;
343 }
344
345 cdg_scroll(cc, cdg_data, &new_frame, inst == CDG_INST_SCROLL_COPY);
346 avctx->release_buffer(avctx, &cc->frame);
347 cc->frame = new_frame;
348 break;
349 default:
350 break;
351 }
352
353 *got_frame = 1;
354 } else {
355 *got_frame = 0;
356 buf_size = 0;
357 }
358
359 *(AVFrame *) data = cc->frame;
360 return buf_size;
361 }
362
363 static av_cold int cdg_decode_end(AVCodecContext *avctx)
364 {
365 CDGraphicsContext *cc = avctx->priv_data;
366
367 if (cc->frame.data[0])
368 avctx->release_buffer(avctx, &cc->frame);
369
370 return 0;
371 }
372
373 AVCodec ff_cdgraphics_decoder = {
374 .name = "cdgraphics",
375 .type = AVMEDIA_TYPE_VIDEO,
376 .id = AV_CODEC_ID_CDGRAPHICS,
377 .priv_data_size = sizeof(CDGraphicsContext),
378 .init = cdg_decode_init,
379 .close = cdg_decode_end,
380 .decode = cdg_decode_frame,
381 .capabilities = CODEC_CAP_DR1,
382 .long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"),
383 };